OTTAWA — In a concession that it has problems regulating itself, the Senate has undertaken a general review of its rules governing spending, in order to bring clarity to how senators can properly make expense claims.

The news came as the Senate agreed to new rules on how members must justify their claims for a housing allowance if they live outside the capital, and as a committee cleared all but three senators on their housing claims.

Senators will now need to furnish a driver’s licence, health card and income tax return to justify their claims of up to $22,000 a year in housing allowances if their main residence is outside the national capital.

The review of housing allowances from about 90 senators — seven others have never taken the allowance — was the first step in an investigation into spending in the Senate. An internal audit is reviewing the clarity of spending rules and red chamber regulations. External auditors are still reviewing the housing claims of three senators — Sen. Mike Duffy, Sen. Mac Harb and Sen. Patrick Brazeau — and a travel bill of more than $300,000 for a fourth, Sen. Pamela Wallin.

The chairman of the Senate’s internal economy committee, Sen. David Tkachuk, said Thursday there would be no further comment from him on the issue “to avoid any question of interference” in the audit.

There is no timeframe for the audits of the four senators to be published, but the government leader in the Senate suggested the exercise of having senators prove their residency claims suggests the rules “need considerable work.”

“I desperately want this cleared up,” said Sen. Marjory LeBreton.

“Once we get the internal audit and the results of the external audit, I am absolutely determined once and for all to ensure … these issues are resolved so the Senate can get the credit it deserves.”

Work has already been done to bring clarity to the rules: The administrative rules of the Senate, which oversee spending, were approved in June 2012, just after a detailed travel policy was approved based on recommendations in previous internal audits. The federal auditor general found in an audit published in 2012 that in a small number of cases, senators weren’t providing enough documentation to support their expense claims.

“Very clearly, this exercise has pointed out that we have considerable work to do to further strengthen and clarify the rules,” LeBreton said.

Under questioning in the Senate, Tkachuk said Duffy’s housing claims were sent straight to the auditors. A committee of senators decided to add Brazeau and Harb to the audit list. Wallin’s travel bill was sent to auditors, but is part of what Tkachuk has said is a series of random audits of senators’ expenses.

“The press speculates on the names of senators and I think it’s detrimental to the reputation of the Senate that there is still doubt, or a witch hunt,” Sen. Serge Joyal told the Senate, before asking Tkachuk to name names for clarity.

Questions about housing expenses arose last year over whether Brazeau lived primarily in Maniwaki, Que., as he claimed on expense forms, or in a home he owned in Gatineau, Que., just across the Ottawa River from the capital. Harb and Duffy are longtime residents of Ottawa but have claimed a housing allowance – Harb by stating his primary residence was in Pembroke, Ont., and Duffy by saying his was in Cavendish, P.E.I.

Duffy has said he did nothing wrong, but last week he pledged to repay an undisclosed amount of the claim. He said the Senate’s expense forms were complicated and the rules of the chamber antiquated.

The form Duffy referred to asks senators to write the address of their primary residence, then mark whether the home is farther than 100 kilometres from Parliament Hill — the standard that allows senators to claim up to $22,000 annually in living expenses in the capital. Senators who qualify can claim about $29 per day if they own or rent a home close to Parliament Hill, or up to $200 per day if they stay in a hotel.

Wallin’s travel expenses, which total more than $300,000 since late 2010, were also sent to an outside auditor, apparently satisfying the committee about her housing claims. Wallin would not comment on the audit when asked at a committee meeting Thursday morning.

On Monday, the committee interviewed two senators because of questions about their paperwork, but cleared Sen. Rod Zimmer from Manitoba and Sen. Dennis Patterson from Nunavut. No other senators were interviewed.

“What a joke,” said NDP ethics critic Charlie Angus. “I think Canadians are fed up with these guys. There’s clearly a huge problem in there, but we have the senators circling the wagons protecting themselves.”